Weathering occurs when materials are eroded or broken down by natural means, such as ice, water and wind. Acid, plants and animals can also cause weathering.
One example of weathering is the Appalachian mountains, which is a very old range that has been weathered over time to be smaller and rounder than younger mountain ranges. Water weathering from the Colorado River created the Grand Canyon, another well-known landmark. Weathering constantly changes the way the Earth looks, though the changes are very slow. Temperature changes can also affect things like rocks because they cause the material to expand and contract. Weathering is a key component of soil creation.